BioCube softiefuge for RSM250

I figured I'd start a thread for the build of my softiefuge since I picked up the BioCube today, so it kinda has to happen at this point lol.

It's going to be a BioCube 14, plumbed in to my Red Sea Max Accessory Kit. The kit provides 2 x 5/8" outlets to the back of the tank. I'll build the overflow box right onto a part of the accessory kit. The bottom of the overflow will be directly in to the DT portion of the BioCube. The return pump will be where the pump from the BC backsump normally pumps into the main tank is. There'll be a pump for a GFO/Carbon reactor installed in the BC backsump.


A BioCube comes with the lighting needed for softies, making it a good option for this project. The BioCube 14G is also the only commonly-available tank over 10G that I can fit in the stand for the RSM, as you can see:


The first problem I realized is that there's an overflow on the BC backsump, so it normally needs to maintain a level there. Gotta do some cutting to let the low water levels reach the return and reactor pump:

 

Seems thought out pretty well. I like that the biocube is like a mini of your main DT. lol

So your biocube will be the fuge? I like the idea, but good luck with the curved front for the baffles.

What's going into the right hand section of your second diagram? Instead of cutting you could just use a bulkhead. Edit: I guess you would have to cut in order to install a bulkhead.

 

Why waste a biocube for a fuge? There are much less expensive ways of doing this.

 

Too late. Already paid for I guess..

 

If he hasn't used/modified it, he can still return it. You can get a custom arylic tank for a lot less also.

 

Ok, so I can pay $110 for a plain acrylic 16G, then pay for shipping on an oversized, delicate item, and have to do all of the same work on an install, and still get lighting for it.

Nah, I'm good with the $140 'cube. There's a local pet store that's going out of business due to some very unusual problems (an interesting story for another thread about corporate arrogance and anti competitive behavior...Stop n Shop is putting this pet store out of business...) that's having a giant sale.

 

Alright, so here's my first update.

I put together the overflow boxes. They're separate right now. They need to be put together on the tank, because I'm using the accessory kit. I refuse to cut the back panel of my tank for this lol.

They're sitting for a leak test right now, but I took some pics.

This is the way it'll sit on the tank assembled, looking from the right side.


This is the outer box. I still need to drill the hole for the drain. The little "Wall" is basically made of silicone lol. It's only 1.6" x ~5" in the bigger half, so it's kinda hard to apply silicone both gracefully and have it be effective for a long period of time.


The outer siphon part. I need to mount the outer box to the black piece, but it would be a pain to assemble now instead of on the tank itself, especially since I need to hook up the return line to the black port that doesn't currently have a tube on it. I don't know if I'll leave that airline tubing in or not, since it would be really hard to put back once the black piece is glued to the box.


The inner box. PVC is there for structural support for the flex tubing; I'll do the same on the outer box.


Oh, and here's a quick lil video of the overflow working. I had to do it, just to be 100% sure it would stop, yet not lose suction lol. I didn't realize that the level in the outer box will pretty much match the inner box at all times.

 

Alright, so now I have the overflow set up on a test rig to figure out the max flow I can put through it. I came up with the whopping number.....60 gph.

The method:

The inner box was inside a pot, the outer had the outlet over the sink. I found a spot where the sink (with a extension hose) was only putting out as much as the overflow can handle, by finding a flow rate on the sink that kept the water level steady in the pot. Then I put the hose in a gallon jug and let it run for 1 minute, and got approximately a gallon of water.

Does that seem wrong to anyone? Should the flow rate be faster with a 5/8" U Tube configuration?

EDIT:
I just put in a flexible tube, 5/8" ID, as the U Tube, and got 90GPH as the max. This still seems low to me, anyone else have an opinion?

 

The inner box snapped when I was putting it on the tank...

 

Probably saved you a big headache down the road. I remember reading one of Steve's threads and you said you "just got back from buying acrylic at Lowes". Well unless your Lowes is different from every other one they only sell extruded acrylic, commonly known as Plexi-glass. Extruded deteriorates quick, turns yellow and gets brittle. Faster when exposed to saltwater. You need to get some cell cast acrylic for tanks and stuff like you're trying to do.
Also I see all your joints appear to be held with silicone. Silicone doesn't bond well with acrylics and all of your joints will eventually fail. You need to use an epoxy made for acrylic. One that melts both surfaces of the joint and forms basically one piece when cured.